Due to the increasing cross-linking of computer resources via the Internet and the constantly increasing demands regarding available storage capacity, cluster storage systems, in particular what are known as “storage clouds,” are increasingly being used instead of a local mass storage system to store large amounts of data. The term “cloud storage” is understood to mean in particular the storage of data in virtualized storage pools provided via a data network, in particular the Internet. Providers who specialize in providing IT services and operate cluster systems make available to a user, generally a commercial user of IT services, comparatively large storage capacities of the cluster system. By outsourcing the provision of the storage capacity to a service provider, a client can reduce the required hardware expense and organizational effort. The service provider can reduce the costs of providing the storage capacity by standardization and the effects of rationalization.
One problem in the use of storage clouds is that a client of the storage cloud provider has no physical control over the stored data and, as a general rule, is also unable to discover what parts of a complex cluster system the data is stored in. Particularly with regard to national data protection guidelines, this regularly presents a problem, if personal or business-critical data are to be stored on a cluster storage system. In particular, it often remains unclear what happens to data stored by the provider when a client of the IT service provider terminates the leased storage capacity.
One possible solution to the above-mentioned problem is to back up only encrypted data in the leased storage space. But secure encryption of large amounts of data requires considerable effort when storing and retrieving the stored data. In addition, advances in decryption technology mean that it is impossible to ensure with absolute certainty that stored data, once encrypted, cannot be decrypted in the future by an unauthorized third party.
It could therefore be helpful to identify other options for secure use of a cluster storage system.